Device comprising lateral injections of liquid for limiting the phenomena of solid deposits in items of equipment with a conical bottom

ABSTRACT

A device for the descending flow of a hydrocarbon-containing liquid containing solid particles at the bottom of an item of equipment (1) and a process for the conversion of hydrocarbon-containing feedstocks implementing said device.

TECHNICAL FIELD OF THE INVENTION

The invention relates to the field of the reduction of deposits ofsediments or of unstable or insoluble molecules in separation anddistillation equipment preferentially with a conical bottom, which areutilized downstream of the refining processes treating heavy or foulingproducts. The invention relates non-limitatively to processes producingliquids capable of fouling items of equipment, such as visbreaking,hydrocracking in an ebullating bed, catalytic cracking, delayed cokingin the refining of oil products as well as the processes of coalliquefaction and biomass treatment.

PRIOR ART

The reduction of deposits fouling items of equipment is a major problemin units for the treatment or conversion of hydrocarbon-containingfeedstocks, in particular for heavy feedstocks. In fact, the fouling ofitems of equipment requires stopping the unit and disassembling it inorder to carry out the cleaning. In the units for the conversion ofhydrocarbon-containing feedstocks in an ebullating bed, in particular,fouling of the walls and of the bottom of the items of separationequipment can be due to particles of asphaltenic nature which flocculateto form solid deposits, molecules which are adsorbed onto the wall, cokeparticles, catalyst fines, metal sulphides based on nickel, iron and/orvanadium or more generally any solid contained in thehydrocarbon-containing feedstock treated.

Patent application U.S. Pat. No. 4,534,851 A describes a method ofintroducing a liquid hydrocarbon-containing feedstock into a transferline to a reaction zone, comprising an injection of steam and of thehydrocarbon-containing feedstock under ascending flow with separateconcentric streams, the stream of hydrocarbon-containing feedstock beingthe inner stream and the stream of steam being the circumferentialstream, and the direction of a portion of the steam towards the innerwall of said transfer line, while the remainder of the steam and thehydrocarbon-containing feedstock are discharged from the zone in adirection parallel to the longitudinal axis.

However this application does not describe a device allowing thereduction of the stagnant zones by recycling the hydrocarbon-containingliquid or an external makeup liquid both inside of thetruncated-cone-shaped part and/or inside the cylindrical part of theitem of equipment.

SUMMARY OF THE INVENTION

The invention relates to a device for the descending flow of ahydrocarbon-containing liquid containing solid particles at the bottomof an item of equipment (1) comprising a cylindrical upper part (11) ofdiameter D1, a truncated-cone-shaped lower part (12) with an angle ofinclination a comprised between 5° and 85° with respect to the verticalaxis (z) of said cylindrical upper part, an outlet pipe (9) of diameterD2, characterized in that it comprises:

-   -   at least one injection (5) of recycled and/or makeup liquid into        the truncated-cone-shaped part (12) of the item of equipment        (1);    -   at least one injection (6) of recycled and/or makeup liquid into        the cylindrical part (11) of the item of equipment (1);

said injection or injections (5) situated in said truncated-cone-shapedpart being inclined with respect to the wall of thetruncated-cone-shaped lower part at an angle β1 in the vertical plane(xz) and at an angle β2 in the horizontal plane (xy); said injection orinjections (6) situated in said cylindrical part being inclined withrespect to the wall of the cylindrical upper part at an angle β1 in thevertical plane (xz) and at an angle θ2 in the horizontal plane (xy), theangles β1 and θ1 being comprised between 5° and 175°, the angles β2 andθ2 being comprised between 90° and 270°.

Advantageously, the device according to the invention comprises a pipe(4) for recycling a part of the liquid leaving said outlet pipe (9),said recycling pipe (4) supplying at least one of said injections (5) or(6) with recycled liquid.

The device according to the invention can comprise a makeup pipe (10)for supplying makeup liquid to at least one of said injections (5) or(6).

Said injections can be distributed by horizontal layers (7) in thetruncated-cone-shaped part and by horizontal layers (8) in thecylindrical part respectively.

Advantageously, the ratio between the diameter D1 of the cylindricalpart and the diameter D2 of the outlet pipe at the bottom of thetruncated-cone-shaped part (D1/D2) is comprised between 1.1 and 1000,preferably between 2 and 500 and preferably between 3 and 100.

Advantageously, the angle α is comprised between 10° and 70°, preferablybetween 15° and 60° and very preferably between 30° and 50°.

Preferably, the angles β1 and θ1 are comprised between 10° and 150°,very preferably between 15° and 120°, more preferably between 15° and90° and yet more preferably between 20° and 60°.

Preferably, the angles β2 and θ2 are comprised between 90° and 180°.

Very preferably, the angles β2 and θ2 are equal to 90°.

Advantageously, the diameter D1 is comprised between 0.1 m and 30 m,preferably between 0.5 m and 20 m, and very preferably between 1 m and10 m.

Advantageously, the height H between two horizontal layers is comprisedbetween 0.01 m and 10 m, preferably between 0.05 m and 5 m and verypreferably between 0.1 m and 1 m.

Preferably, the number of injections N per layer is comprised between 1and 30.

Preferably, the number of injections per layer is comprised between 2and 20, said injections within one and the same layer being spaced at anangle δ equal to 360/N where N denotes the number of injections perlayer.

Very preferably, the number of injections per layer is comprised between2 and 10, yet more preferably between 2 and 6.

Preferably, the item of equipment (1) is a means for the separation ofgas/liquid allowing hydrocarbon-containing feedstocks to be treated.

The invention also relates to a process for the conversion ofhydrocarbon-containing feedstocks implementing said device.

Preferably, said process implements a hydroconversion step in anebullating bed for feedstocks containing hydrocarbon fractions of whichat least 50% by weight have a boiling temperature greater than 300° C.

The velocity V of the liquid injected in said injections isadvantageously comprised between 0.05 m·s⁻¹ and 40 m·s⁻¹, preferablybetween 0.1 m·s⁻¹ and 30 m·s⁻¹ and very preferably between 0.5 m·s⁻¹ and10 m·s⁻¹.

The injection rate of liquid injected by the injections (5) and (6) withrespect to the liquid circulating in the item of equipment (1) isadvantageously comprised between 1% and 400%, preferably between 5% and100%, very preferably between 10% and 60% and yet more preferablybetween 20 and 50%.

BRIEF PRESENTATION OF THE FIGURES

Other characteristics and advantages of the device according to theinvention will become apparent on reading the following description ofnon-limitative embodiment examples, with reference to the attachedfigures which are described below.

FIG. 1: FIG. 1 shows the schematic diagram of the device according tothe invention.

FIG. 2: FIG. 2 shows the utilization of the injections of recycledhydrocarbon-containing and/or makeup liquid inside the cylindrical andtruncated-cone-shaped parts of the item of equipment.

FIG. 3: FIG. 3 shows the device according to the invention and theutilization of multiple lateral injections of liquid into thecylindrical and truncated-cone-shaped parts of the item ofequipment—Front view and top view: (3A) multiple injections (6) into thecylindrical part of the item of equipment 1; (3B) multiple injections(5) into the truncated-cone-shaped part of the item of equipment 1

FIG. 4: FIG. 4 (4A: isometric view 4B: top view) shows for theconfiguration without injection, the parts of the item of equipmentwhere the volume fraction of the solid phase is greater than 0.1% byvolume. These zones show the zones where solid particles haveaccumulated.

FIG. 5: FIG. 5 shows for the configuration with injections, the parts ofthe item of equipment where the volume fraction of the solid phase isgreater than 0.1% by volume.

DETAILED DESCRIPTION OF THE INVENTION

Generally, the invention relates to any item of equipment in which ahydrocarbon-containing liquid circulates with the possibility ofstagnation and accumulation of solid particles at the bottom of the itemof equipment. More particularly, the device according to the inventionis situated in the lower part of an atmospheric or vacuum distillationcolumn, separation drum or any other means of gas/liquid separationmaking it possible to treat hydrocarbon-containing feedstocks.

In the remainder of the text, by “injection” is meant any means known toa person skilled in the art making it possible to inject liquid from thewall of the item of equipment to the inside, said means being suppliedby at least one pipe for transporting liquid.

FIG. 1 shows the schematic diagram of the invention.

The invention is implemented in an item of equipment (1) with a conicalbottom, i.e. comprising a cylindrical upper part (11) and atruncated-cone-shaped lower part (12) where a foulinghydrocarbon-containing liquid (2) (i.e. a liquid containing solidparticles or compounds capable of flocculating or adsorbing onto thewall) flows in a descending manner from the top of the item of equipmentand leaves through an outlet pipe (9). The truncated-cone-shaped form iswell known to a person skilled in the art for minimizing the deposit inthe bottom by facilitating the drainage of the solids by gravity to theoutlet pipe. In order to reduce the formation of the deposits on thewall and in the bottom of the item of equipment, the device compriseslateral injections of recycled and/or makeup liquid: injections into thetruncated-cone-shaped part (5) and injections into the cylindrical part(6). These injections can be distributed to the wall along horizontallayers in the truncated-cone-shaped part (7) and along horizontal layersin the cylindrical part (8). The outgoing liquid stream is dischargedfrom the item of equipment via a discharge pipe (3).

In a first embodiment of the invention, a makeup pipe for liquid (whichcan be a fluxing liquid) (10) supplies the lateral injections (5) and(6) situated in the truncated-cone-shaped part and in the cylindricalpart, in order to reduce the stagnant zones in the item of equipment (1)and to limit the deposits of solid particles on the walls. Any cut witha boiling point greater than or equal to the boiling point of thehydrocarbon-containing liquid supplying the item of equipment (1), forexample catalytic cracking effluent (HCO), LCO, or any other VGO, AR,VR, DAO cut, aromatic extract, can be suitable as makeup liquid.According to this embodiment the flow rate of liquid leaving via thedischarge pipe (3) is equal to the sum of the flow rate ofhydrocarbon-containing liquid circulating in the item of equipment (2)and the flow rate of makeup liquid injected into the makeup pipe (10).The makeup liquid injected through the makeup pipe (10) makes itpossible to reduce the stagnant zones by generating a turbulence in theitem of equipment (1) in order to limit the deposits of solid particleson the walls. Said injected makeup liquid can also act as a flux whenthe chosen liquid is an aromatic base.

According to another embodiment of the invention, a part of thehydrocarbon-containing liquid leaving the item of equipment (1) can berecycled in order to supply the lateral injections (5) and (6).According to this embodiment the flow rate of liquid leaving via thedischarge pipe (3) is equal to the flow rate of liquid (2). The liquidrecycled through the recycling pipe (4) makes it possible to reduce thestagnant zones in the item of equipment (1) by generating a turbulencein order to limit the deposits of solid particles on the walls.

According to a last embodiment of the invention, the liquid injectedinto the lateral injections (5) and (6) can originate both from therecycling pipe (4) and from the makeup liquid pipe (10). According tothis embodiment, the flow rate of liquid leaving via the discharge pipe(3) is equal to the sum of the flow rate of hydrocarbon-containingliquid circulating in the item of equipment, called fouling liquid (2),and the flow rate of makeup liquid injected into the makeup pipe (10).The liquid injected through the makeup pipe (10) and through therecycling pipe (4) makes it possible to reduce the stagnant zones bygenerating a turbulence in the item of equipment (1) in order to limitthe deposits of solid particles on the walls and can also act as a fluxas mentioned previously.

The liquid injected by the lateral injections (5) and (6) can thereforebe liquid recycled from the item of equipment (1) and/or makeup liquid,i.e. a liquid originating from outside of the item of equipment (1).

The injection rate of the liquid injected by the lateral injections (5)and (6) is defined as being the ratio between the sum of the flow rateof liquid in the recycling pipe (4) and the flow rate of liquid in themakeup pipe (10) to the flow rate of hydrocarbon-containing liquidcirculating in the item of equipment or fouling liquid (2).

The feedstock entering the device can contain any type of compoundsoriginating from an effluent of a hydroconversion process, for exampleoriginating from an H-OIL™ ebullating bed unit, but also any type ofcompounds originating from a slurry hydroconversion process, from afixed bed, moving bed, fluidized bed hydrotreatment process, catalyticcracking (FCC) effluent, effluents from thermal conversion processessuch as coking, visbreaking, and any other separation process such asfor example solvent deasphalting.

The solid particles can be precipitated asphaltenes, supported orunsupported catalyst fines (usually with a diameter of less than 500microns) or coke particles, sulphides of metals such as nickel,vanadium, iron, molybdenum.

The flow in the device is descending, the device according to theinvention can be utilized at the bottom of a vacuum distillation columnor at the bottom of an atmospheric column or at the bottom of anygas-liquid separator.

FIG. 2 shows the different types of lateral injections of the recycledpart of the liquid or of the makeup liquid.

The item of equipment 1, which can be for example a distillation columnor a separator, has a cylindrical upper part (11) of diameter D1, atruncated-cone-shaped lower part (12), an outlet pipe (9) situated atthe bottom of the item of equipment, through which thehydrocarbon-containing liquid leaves, of diameter D2. Thetruncated-cone-shaped part (12) (also called conical bottom) has anangle of inclination a, with respect to the vertical wall of thecylindrical part, indicated by the axis z. Two types of injection ofliquid (makeup or recycled) are defined:

-   -   Injections (5) into the truncated-cone-shaped part of the item        of equipment (1).    -   Injections (6) into the cylindrical part of the item of        equipment (1).

Injections (5) situated in the truncated-cone-shaped part (12) areinclined with respect to the wall of the conical bottom at an angle β1in the vertical plane (xz) and at an angle β2 in the horizontal plane(xy), x denotes the horizontal axis, z denotes the vertical axis of thecylindrical part perpendicular to the horizontal plane (xy).

The injections (6) situated in the cylindrical part (11) are inclinedwith respect to the wall of the cylindrical body at an angle θ1 in thevertical plane (xz) and at an angle θ2 in the horizontal plane (xy).

The injections are advantageously orientated in the same direction ofrotation in the horizontal plane (xy) and advantageously situated in theliquid part of the column bottom.

FIG. 3A shows the utilization of multiple of injections (6) in thecylindrical part (11) of the item of equipment (1), FIG. 3B shows theutilization of multiple of injections (5) in the truncated-cone-shapedpart (12) of the item of equipment (1).

Placing the injections into the wall of the item of equipment is carriedout according to horizontal layers (8) in the plane (xy) for injections(6) into the cylindrical part (11) and according to horizontal layers(7) for injections (5) into the truncated-cone-shaped part (12). Eachlayer of injections (7) in the truncated-cone-shaped part (12) and (8)in the cylindrical part (11) comprises respectively a number N ofinjections (5) or (6) located at the same height on the axis (z). InFIG. 3, N is equal to 2. Each layer is separated by a height H. Withinone layer, each injection is separated from the next by an angle δ equalto 360/N in the plane (xy). As shown in FIG. 3, a layer of injectionscan be offset with respect to another layer of injections by an angle γin the plane (xy).

The number of layers in each of the truncated-cone-shaped or cylindricalparts is advantageously comprised between 1 and 20, preferably between 1and 10 and preferably between 1 and 6.

The velocity V of the liquid injected into the lateral injection pipes(5) and (6) is advantageously comprised between 0.05 m·s⁻¹ and 40 m·s⁻¹,preferably between 0.1 m·s⁻¹ and 30 m·s⁻¹ and very preferably between0.5 m·s⁻¹ and 10 m·s⁻¹. Preferably, the diameters of the injection pipesare sized as a function of the flow rate of liquid to be injected inorder to obtain the desired injection speeds.

The flow rate of liquid recycled via the recycling pipe (4) plus theflow rate of liquid injected via the pipe (10) to the flow rate ofhydrocarbon-containing liquid (2) circulating in the item of equipment(1) is advantageously comprised between 1% and 400%, preferably between5% and 100%, very preferably between 10% and 60% and yet more preferablybetween 20 and 50%.

The diameter D1 of the cylindrical part (11) of the item of equipment(1) is advantageously comprised between 0.1 m and 30 m, preferablybetween 0.5 m and 20 m, and very preferably between 1 m and 10 m.

The ratio between the diameter D1 of the cylindrical part (11) and thediameter D2 of the outlet pipe (9) at the bottom of thetruncated-cone-shaped part (D1/D2) is advantageously comprised between1.1 and 1000, preferably between 2 and 500 and preferably between 3 and100.

The angle α is the angle of inclination of the truncated-cone-shapedpart with respect to the vertical wall (axis z) of the cylindrical partand is advantageously comprised between 5° and 85°, preferably between10 and 70°, very preferably between 15 and 60° and yet more preferablybetween 30 and 50°.

The angles β1 and θ1 are comprised between 5° and 175° with respect tothe wall of the truncated-cone-shaped part and to the wall of thecylindrical part respectively, preferably between 10° and 150°, verypreferably between 15° and 120° and more preferably between 15° and 90°and yet more preferably between 20° and 60°.

The angles β2 and θ2 are comprised between 90° and 270° with respect tothe diameter along the axis γ of the cylindrical section, and preferablybetween 90° and 180°. Very preferably, the angles β2 and θ2 are equal to90°.

The number of injections N through the wall of the item of equipment,into each horizontal layer (8) in the cylindrical part (11) and intoeach horizontal layer (7) in the truncated-cone-shaped part (12) iscomprised between 1 and 30, preferably between 2 and 20, very preferablybetween 2 and 10, most preferably between 2 and 6. Each layer, whetherwithin one and the same part or in both parts, can have a differentnumber of injections N.

The height H between two layers is advantageously comprised between 0.01m and 10 m, preferably between 0.05 m and 5 m and very preferablybetween 0.1 m and 1 m.

The angle δ separating the injections in the circumference of one andthe same layer is comprised between 0° and 180°, preferably between 5°and 120°, very preferably between 10° and 90°. Advantageously, the angleδ is equal to 360/N where N denotes the number of injections per layer.

The angle γ denotes the angular offset of one layer with respect to theother. This angle can be comprised between 0° and 180°, preferablybetween 5° and 120°, very preferably between 10° and 90°.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The preceding preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

In the foregoing and in the examples, all temperatures are set forthuncorrected in degrees Celsius and, all parts and percentages are byweight, unless otherwise indicated.

The entire disclosures of all applications, patents and publications,cited herein and of corresponding application No. FR 1759606, filed Oct.13, 2017 are incorporated by reference herein.

EXAMPLES

Computational Fluid Dynamics (CFD) mechanical simulations of theliquid/particles flow in an item of equipment with a conical bottomwithout injections (comparative) and in the same item of equipment witha conical bottom comprising a device with lateral injections of recycledliquid according to the invention were carried out using the Barracuda™software. This software uses a Eulerian approach for the fluid phase anda pseudo-Lagrangian approach for the particulate phase (see publicationD. M. Snider, An Incompressible Three-Dimensional MultiphaseParticle-in-Cell Model for Dense Particle Flows, Journal ofComputational Physics 170 (2001), 523-549).

Table 1 presents the simulated conditions, as well as thecharacteristics and dimensions of the item of equipment, including thedevice according to the invention (number of injections, number oflayers, angles of injection).

TABLE 1 Dimensions of the item of equipment Diameter D1 (m) 1.2 DiameterD2 (m) 0.25 Angle α 45° Number of layers in the cylindrical part 1Number of layers in the truncated-cone- 1 shaped part Number ofinjections per layer 2 Angle β1 and θ1 30° Angle β2 and θ2 90° Operatingconditions Density of hydrocarbon-containing liquid (2) 990 (kg/m³) Flowrate of circulating hydrocarbon- 7.5 containing liquid (2) (kg/s)Injection rate (flow rate of the recycled liquid 30% in the pipe (4) toflow rate of circulating hydrocarbon-containing liquid (2)) Density ofsolid particles (kg/m³) 2800 Diameter of solid particles (microns) 50Flow rate of solid particles (kg/s) 0.02

FIG. 4 (4A: isometric view, 4B: top view) shows for the configurationwithout injection (comparative), the parts of the item of equipmentwhere the volume fraction of the solid phase is greater than 0.1% byvolume. These zones represent the zones of accumulation of solidparticles.

FIG. 5 shows for the configuration with injections according to theinvention, the parts of the item of equipment where the volume fractionof the solid phase is greater than 0.1% by volume, in a top view.

By comparing FIG. 4B and FIG. 5, a reduction in the zones ofaccumulation of solids is observed thanks to the utilization of thelateral injections of liquid with the device according to the invention.Calculating by volume, it appears that in the configuration according tothe invention, with a recycling of 30% of the hydrocarbon-containingliquid for supplying two injections into the truncated-cone-shaped partand two injections into the cylindrical part with a geometry accordingto the invention, the number of accumulation zones as defined previouslywas divided by 30.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. Device for the descending flow of a hydrocarbon-containing liquidcontaining solid particles at the bottom of an item of equipment (1)comprising a cylindrical upper part (11) of diameter D1, atruncated-cone-shaped lower part (12) with an angle of inclination acomprised between 5° and 85° with respect to the vertical axis (z) ofsaid cylindrical upper part, an outlet pipe (9) of diameter D2,characterized in that it comprises: at least one injection (5) ofrecycled and/or makeup liquid into the truncated-cone-shaped part (12)of the item of equipment (1); at least one injection (6) of recycledand/or makeup liquid into the cylindrical part (11) of the item ofequipment (1); said injection or injections (5) situated in saidtruncated-cone-shaped part being inclined with respect to the wall ofthe truncated-cone-shaped lower part at an angle β1 in the verticalplane (xz) and at an angle β2 in the horizontal plane (xy); saidinjection or injections (6) situated in said cylindrical part beinginclined with respect to the wall of the cylindrical upper part at anangle θ1 in the vertical plane (xz) and at an angle θ2 in the horizontalplane (xy), the angles β1 and θ1 being comprised between 5° and 175°,the angles β2 and θ2 being comprised between 90° and 270°.
 2. Deviceaccording to claim 1 comprising a pipe (4) for recycling a part of theliquid leaving said outlet pipe (9), said recycling pipe (4) supplyingrecycled liquid to at least one of said injections (5) or (6).
 3. Deviceaccording to claim 1 comprising a makeup pipe (10) for supplying makeupliquid to at least one of said injections (5) or (6).
 4. Deviceaccording to claim 1 in which said injections are distributed byhorizontal layers (7) in the truncated-cone-shaped part and byhorizontal layers (8) in the cylindrical part respectively.
 5. Deviceaccording to claim 1 in which the ratio between the diameter D1 of thecylindrical part and the diameter D2 of the outlet pipe at the bottom ofthe truncated-cone-shaped part (D1/D2) is comprised between 1.1 and1000, preferably between 2 and 500 and preferably between 3 and
 100. 6.Device according to claim 1 in which the angle α is comprised between10° and 70°, preferably between 15° and 60° and very preferably between30° and 50°.
 7. Device according to claim 1 in which the angles β1 andθ1 are comprised between 10° and 150°, very preferably between 15° and120°, more preferably between 15° and 90° and yet more preferablybetween 20° and 60°.
 8. Device according to claim 1 in which the anglesβ2 and θ2 are comprised between 90° and 180°.
 9. Device according toclaim 8 in which the angles β2 and θ2 are equal to 90°.
 10. Deviceaccording to claim 1 in which the diameter D1 is comprised between 0.1 mand 30 m, preferably between 0.5 m and 20 m, and very preferably between1 m and 10 m.
 11. Device according to claim 4 in which the height Hbetween two horizontal layers is comprised between 0.01 m and 10 m,preferably between 0.05 m and 5 m and very preferably between 0.1 m and1 m.
 12. Device according to claim 4 in which the number of injections Nper layer is comprised between 1 and
 30. 13. Device according to claim12 in which the number of injections per layer is comprised between 2and 20, said injections within one and the same layer being spaced at anangle δ equal to 360/N where N denotes the number of injections perlayer.
 14. Device according to claim 13 in which the number ofinjections per layer is comprised between 2 and 10, preferably between 2and
 6. 15. Device according to claim 1 in which said item of equipmentis a means for the separation of gas/liquid allowinghydrocarbon-containing feedstocks to be treated.
 16. Process for theconversion of hydrocarbon-containing feedstocks implementing a deviceaccording to claim
 1. 17. Process according to claim 16 implementing ahydroconversion step in an ebullating bed for feedstocks containinghydrocarbon fractions of which at least 50% by weight have a boilingtemperature greater than 300° C.
 18. Process according to claim 16 inwhich the velocity V of the liquid injected in said injections iscomprised between 0.05 m·s⁻¹ and 40 m·s⁻¹, preferably between 0.1 m·s⁻¹and 30 m·s⁻¹ and very preferably between 0.5 m·s⁻¹ and 10 m·s⁻¹. 19.Process according to claim 16 in which the injection rate of recycledand/or makeup liquid with respect to the hydrocarbon-containing liquidcirculating in the item of equipment is comprised between 1% and 400%,preferably between 5% and 100%, very preferably between 10% and 60% andyet more preferably between 20 and 50%.